Patent GB-1140917-A (GB)
Title: Improvements in or relating to clamping arrangements for clamping cylindrical members in holders
IPC: H01J19/74
Filed: 1965-12-03
Abstract: 1,140,917. Clamps. M-0 VALVE CO. Ltd and C. A. TREMLETT. 3 March, 1967 [3 Dec., 1965], No. 51423/65. Heading E2B. [Also in Division Hl] A clamping arrangement for clamping a cylindrical member 4 comprises a holder 24 a first set of flat annular members 27 which are interleaved with a second .set of flat an-. nular members 28, the second set of annular members being held in place relative to the holder and the two sets of annular members 'being disposed substantially co-axially so that their internal surfaces define a. substantially cylindrical recess adapted to receive the cylindrical member; and means operative to cause the annular members of .said first set to contract in a radial sense and thereby grip the cylindrical member when positioned in the recess or to expand in the radial sense thereby releasing the cylindrical member. In a modified construction each set of annular members is replaced with a helix the two helices being interwound. In the construction shown each annular member 27 is provided with two slots on opposite sides of a split in the member and both sets of members are received in a cylindrical bore 25 in the holder 24. Extending lengthways along the bore 25 is a key way into which fits a key 31 which also fits into one of the slots in each of the split rings 27 thereby fastening one end of each split ring 27 to the holder 24. The means for causing the annular members 27 to contract and expand consists of a rectangular metal plate 32 a 'threaded rod 34 and a knob 35. The plate 32 is housed in a slot in the holder which opens into the bore 25 and along its inner edge the plate 32 is provided with a projecting claw 33 which fits into the other .slot in each of the members 27. The threaded rod 34 is mounted in a tapped hole formed in the holder and the outer end of the rod projects from the holder and is provided with the knob 35 for rotating the rod. The members 28 fit tightly in the bore and each is partly cut away to allow the slotted portions of -the members 27 to project clear of the members 28. Rotating the knob 35 in one direction moves the plate 32 inwardly and thereby urges the ends of each member 27 together; when the knob 35 is rotated in the other direction the plate 32 can move outwardly owing to the resilience of the members 27 which expand radially. In the construction in which the annular members are replaced by helical springs the ends of one helix are secured to the holder so that the outer ..surface of this helix fits tightly against the internal surface of the bore 25 and the other helix is secured to the holder at one end and its other end is provided with a mechanism whereby this end the other end. The holder 24 is secured to one direction of rotation contracts the helix and the other direction expands it. The arrangement described is used for clamping in position one end of a travelling wave tube, the holder 24 being in the form of a rectangular metal block, four faces of which are provided with a plurality of parallel spaced-apart cooling fins 26 for cooling the collector electrode of the travelling wave tube,-the electrode consisting of the cylindrical member 4 which is clamped by the members 27 or by the helix and a metal tubular member 3 of circular cross section which is sealed to the member 4 at one end and to a glass envelope 1 at the other end. The holder 24 is secured to one end of a framework 10 made of aluminium and which includes a central elongated portion 11 inside which extends a longitudinal array of annular magnets 7 which are magnetized in an axial sense and which are arranged co-axially with each adjacent pair of magnets 7 having like poles adjacent each other; the magnets are spaced apart by a series of similar annular soft iron pole pieces 8 and they are mounted on a support tube of circular cross section. The elongated portion 11 has its ends secured to two annular end blocks 12 one of which is shown. Each block 12 fits around two flat rectangular ,blocks 17 of permanently magnetized material associated with pole :pieces 15, the blocks 17 being respectively disposed adjacent the narrow wall 16 of a waveguide 13 each of the broader walls 14 of which has a circular aperture formed in it through which passes a narrow portion 2 of the envelope 1 of the travelling wave tube. The blocks 17 are held in position in the end block 12 by a cover plate 18.